Heater core?

Is there a way to find out and inspect the heater core for coolant leak without removing the dashboard ? Unable to do soap test due to dashboard. The vehicle has no external leaks. Dye doesn't appear in oil or external under the hood. Leak down test hold pressure. Im assuming heater core maybe has slow weep that doesn't drip. Maybe dries up and cakes at leak point.

What is the vehicle your working on? You might be able to tell if the heater core is leaking by two methods other than visibly seeing the leak. One is to put the controls on defrost and see if the windshield fogs up. Another is to smell the air from the vents. If it smells sweet then you have a heater core leak

HTH

You could isolate the heater from the engine blow the coolant out and do an air pressure leak down test or a vacuum leakdown test on it but I wouldn't rule out an inlet manifold or head gasket leak. Aslow leak that goes into the combustion chamber any dye will get burned up and not show any trace in the oil and a leak into the inlet won't show up as combustion gases in the coolant.

The gaskets are new. Heads was pressure tested and are good. Leek down tested no pressure in coolant tank. The dye didn't show anywhere. The coolant hand pump test holds 15 psi left on for 30 minutes. I want able to find any leak.

I have seen it once in my practice when rad was leaking internally, into tranny cooler.Do you have one?we still don't know the car.

Isolate the heater and nothing more. Just run the car and see if the problem is solved. I know that's not what you asked but definitely the easiest way to find the answer.

There is one problem with testing by clamping off the heater hoses on many cars with air blending heaters (those don't use a water valve) the warm bypass coolant flow through the heater circuit and back through the block is required for the thermostat to open.

This is on a Freelander Land Rover

I have separate transfer cooler and all other fluid levels have not increased. And isn't showing the dye in it. It's an odd issue.

Freelanders have a lot of different engine types.
On the Freelander 1 on all engine types the coolant tank caps are always suspect I pressure test them insitu ---- if it is the 4 cylinder K16 1.8 there is a fair chance it is inlet manifold gasket.
It could also be the O ring on the steel water pipe that runs along the rear of the rear of the block to the thermostat housing. It is vital that the bolts that clamp the supports for this tube are properly fitted.
Also check the O ring between the original thermostat housing and the engine can also leak.

You say the head gasket was changed were the liner heights checked ? and what gasket type was used ? These days I always use the latest Chinese MG SAIC gasket, the multilayer (MLS) gasket developed durring the Ford ownership years only works for a narrower range of liner heights than the original Payne Rover gasket and even if the liner heights meet the spec it tends to weep. If liners have sunk in the block lower than spec it is fairy easy to fix by pulling the liner out and fitting shims below the liner.

The KV6 can also suffer liner issues but too a lesser extent the most common cooling issue on these is a cracked thermostat.
All models can suffer from cracks in the plastic T pieces

The gasket was oem I have also used an aftermarket gasket in the past reinz brand MLS neither has made any difference. The liners were leveled with block deck. On the kv6 model I had the opportunity to pull out the liners and these liners sit on top of a step in the block and can't sink lower unlike the discovery engine which there is no seat for the liner in which they can sink down. So the liners seemed leveled. I do not have any pressurized exhaust going into system. So it seems to be sealed at head gasket. I checked the oring and plastic no leaks. I know on the discovery if liner sinks you get pressure build up in system or system doesn't hold pressure depending on how it is sealing at gasket.

The liners should sit proud of the block.
The genuine Ford LandRover MLS with the sticky shim plate was robust but can weep externally and can only cope with liner heights that are even and 0.003" to 0.007" pround of the block. Pattern MLS gaskets aren't nearly as good as the genuine ones.

The SAIC gasket is a major re-engineering of the gasket it will cope with a wide variation in liner height the fire rings are thicker and compress more and the outer gasket ia thicker and more compliant.

Carstuff wrote: The gaskets are new. Heads was pressure tested and are good. Leek down tested no pressure in coolant tank. The dye didn't show anywhere. The coolant hand pump test holds 15 psi left on for 30 minutes. I want able to find any leak.

At what engine temp are you doing this pressure test? You should do it both cold and hot. Had one years ago with a leaking water pump that would not leak a drop when hot.

Agree re blocking the heater. We sometimes use a 5/8 double ended barb. There's always a way anyway. We see these engines in Kia carnivals (People mover). They were a total flop over here. The block would go soft after overheating and let the liners come loose. The retainer or ledge of the liner is at the bottom and would get pulled down into the crankcase and let coolant into the combustion chamber.
I've seen the result first hand but never pulled one apart. That's what our reconditioner told us happened anyway.

A couple of shots of fairly typical inlet K16 leaks --- very hard to spot

Note rust trace on cylinder head.

Starngely the liners are meant to be a fairy loose fit, a lot of the problems came in the early 1990's with a revision in the way the block was cast and a whole load of relatively minor installation issues.
On these post 1995 engines liners should sit just proud of the block.
There are shims available to fit under the liner and fitting them is simple ! a matter of disconnecting the big end bearing and gripping the liner by hand and pulling it out complete with piston.

The shim or shim is then fitted over the bottom of liner which is coated with a generous coating of non-hardening jointing paste and slipped back into place.

Im doing the test cold. I checked water pump it's dry no dye anywhere. It's strange.

Yeah I apologise Andy. Getting my rover motors completely confused. Please continue and ignore my late night rambles.

The second pressure hot and cold test showed same result. It holds pressure and I checked all over and did not notice any dye. When you pump the reservoir up the pressure from pump seems to compress the fluid down to empty the reservoir and after removing the pressure the fluid comes back to the full mark as before test was performed.

What's your thoughts on using an additive for stopping small leaks ?